Bhagavad Gītā Chapter Nine Title

rājavidyā rājaguhya yogaḥ

The Yoga of Sovereign True Knowledge and Sovereign Mystery.

rāja - a king, sovereign, chief or best of its kindvidyā - any knowledge whether true or false; knowledge of the soul or spiritual knowledge; true knowledgeguhya - mysteryyoga - the act of yoking

Commentaries and Reflections

Commentary by Paul Harvey:

The Yoga of the highest knowledge, the highest secret.